Lysosomal cysteine proteases: more than scavengers

Area of Science:

• Biochemistry
• Cell Biology
• Enzymology

Background:

• Lysosomal cysteine proteases traditionally viewed as intracellular protein degraders.
• Emerging evidence reveals extracellular roles and involvement in pathology.
• Discovery of novel cathepsins with specific tissue distributions suggests broader functions.

Purpose of the Study:

• To review the physiological roles of mammalian lysosomal papain-like cysteine proteases.
• To discuss their mechanisms of action.
• To examine the regulation of their enzymatic activity.

Main Methods:

• Literature review and synthesis of current research.
• Analysis of studies on cathepsin function and regulation.
• Discussion of enzyme mechanisms and tissue-specific roles.

Main Results:

• Cathepsins perform diverse cellular tasks beyond simple degradation.
• Specific cathepsins exhibit restricted tissue distributions, indicating specialized functions.
• Extracellular activity of cathepsins is linked to pathological conditions.

Conclusions:

• Mammalian lysosomal papain-like cysteine proteases have multifaceted physiological roles.
• Understanding their specific functions and regulation is crucial for comprehending cellular processes and disease.
• Further research is needed to fully elucidate the complex activities of these enzymes.